Multisegment filter of the tobacco processing industry and method for the production thereof

ABSTRACT

The invention relates to a multi-segment filter ( 70 ) of the tobacco processing industry with at least two filter segments ( 60 - 62 ) arranged one behind the other in a longitudinally axial manner, and to a method for producing a multi-segment filter ( 70 ) of the tobacco processing industry, whereby a group of filter segments ( 60 - 62 ) is assembled and whereby the group of filter segments ( 60 - 62 ) is wrapped with a first wrapping material ( 65 ) to form a multi-segment filter ( 70 ). The multi-segment filter according to the invention is characterized in that a compressible and/or elastic first wrapping material ( 65 ) is arranged outside around the filter segments ( 60 - 62 ). The method according to the invention is characterized in that the first wrapping material ( 65 ) is compressible and/or elastic.

[0001] The invention relates to a multi-segment filter of the tobacco processing industry with at least two filter segments arranged one behind the other in a longitudinally axial manner, and to a method for producing a multi-segment filter of the tobacco processing industry, whereby a group of filter segments is assembled and whereby the group of filter segments is wrapped with a first wrapping material to form a multi-segment filter.

[0002] Corresponding multi-segment filters are used, e.g., to filter the smoke of cigarettes accordingly with various substances or materials. Thus a multi-segment filter can, e.g., be composed of segments such as, e.g., conventional cellulose acetate that is made of a cellulose acetate tow with a softener and is permeable to smoke, filter segments with activated carbon particles, sintered pellets, empty casings or casings filled with granulate, fibrous web, etc.

[0003] U.S. Pat. No. 4,026,306 describes a three-fold filter (cavity/plug/cavity) that is wrapped with a cellulose acetate tow, whereby the acetate is used as a filter medium and the plug is used to deflect the smoke through the filter material.

[0004] U.S. Pat. No. 3,492,998 shows a filter that is made of filter material disks and that is encased by two jackets, whereby the jackets are made of paper, cork or a plastic material such as polyethylene.

[0005] Corresponding multi-segment filters are produced, e.g., with a so-called Mulfi-E of the applicant. This is a production line for producing double filter rods from different basic filter rods. The Mulfi-E production line comprises the so-called GC-E for cutting and grouping the basic filter rods and a KDF 2E filter rod-making machine for wrapping the double filter segments and for cutting the 4-fold or 6-fold double filter rods. These machines are known to the specialist trade and the specialist public. In principle a corresponding device with which a process for producing multi-segment filters can be carried out is described in DE-OS 15 34 666. Of course, it is also possible to provide not just two filter segments, but a plurality of filter segments, as described, e.g., in DE 101 46 917.9 of the applicant with the title “Device for Assembling Groups of Filter Segments for Producing Multi-segment Filters of the Tobacco Processing Industry and Fluted Drum.” The disclosure of the cited documents is expressly incorporated in this patent application in its entirety.

[0006] Due to the production tolerances of the diameters of the filter segments, in particular with hard filter segments, such as, e.g., extruded filter segments or filter segments produced in an injection molding process, in the production of multi-segment filters it can lead to filter segments featuring different diameters being arranged next to one another. If these filter segments, as is usual, are wrapped with a wrapping material of paper, or, as in U.S. Pat No. 3,492,998, with a polyethylene, an undesired effect can occur that a cavity develops between the wrapping material and at least one filter segment, which can mean that smoke can be drawn through this hollow space, avoiding the filter effect of the corresponding filter element with smaller diameter. This means that the filter properties of the multi-segment filter can be undesirably changed or in part completely neutralized. Another difficulty is that, in the case of filters with hard segments, during the wrapping of the cigarette/filter/cigarette group with wrapping paper damage can occur to the hard segments or the wrapping paper can be damaged due to the incompressibility of the hard segments and the compressibility of the cigarettes and the soft segments of the filters.

[0007] Accordingly, it is the object of the present invention to avoid these disadvantages and to disclose a multi-segment filter and a method for producing a multi-segment filter of the tobacco processing industry, by means of which corresponding production tolerances of filter segments can be equalized so that no cavities can develop by means of which the smoke can be guided past the filter segments.

[0008] This object is attained through a multi-segment filter of the tobacco processing industry with at least two filter segments arranged one behind the other in a longitudinally axial manner, that is further developed in that a compressible and/or elastic first wrapping material is arranged outside around the filter segments.

[0009] By providing a compressible and/or elastic wrapping material, differences in diameter of the filter segments can be compensated for in a very elegant way.

[0010] The compressible and/or elastic first wrapping material is arranged around the filter segments in particular in a longitudinally axial manner. By using a compressible first wrapping material there is the further advantage that from the outside a multi-segment filter can be produced that is very uniform in terms of diameter, which would not be the case if, e.g., only an elastic material were used as first wrapping material.

[0011] A particularly preferred embodiment of a multi-segment filter according to the invention is given if the first wrapping material is essentially impermeable to smoke or completely impermeable to smoke. Through this preferred embodiment of the multi-segment filter according to the invention no smoke at all gets past the desired filter materials, even in the case of differences in diameter. Ventilation holes are preferably provided in the first wrapping material, as otherwise with normal wrapping material. If the first wrapping material is the outermost layer of the multi-segment filter, a particularly simple and quick production of the multi-segment filter is possible which is also cost-effective.

[0012] If a second wrapping material is arranged outside around the first wrapping material, customary outermost wrapping materials can be used which hitherto have also been used in the production of multi-segment filters.

[0013] The first wrapping material preferably comprises a closed-pore foam. A correspondingly closed-pore foam is on the one hand essentially impermeable to smoke and on the other hand can be embodied such that a compressibility is rendered possible even in the case of low acting forces. Preferably, the first wrapping material consists of a closed-pore foam.

[0014] If the closed-pore foam comprises foamed cellulose acetate, a material can be used that is very well known regarding its composition in the tobacco processing industry for producing filters. In contrast to the cellulose acetate produced from a tow with softener, the foamed cellulose acetate is hereby also essentially impermeable to smoke. The closed-pore foam is preferably composed of foamed cellulose acetate. The closed-pore foam is preferably a hot melt foam such as, e.g., ethylene vinyl acetate copolymer.

[0015] The first wrapping material preferably comprises or is composed of hot melt adhesive such as, e.g., an ethylene vinyl acetate copolymer. Alternatively, the first wrapping material can comprise and/or be composed of a cellulose acetate tow with marked rippling and without a softener such as, e.g., triacetin. Furthermore, the first wrapping material can be an air-layed fibrous web that is produced according to a process that is described in EP 003 20 44 B1.

[0016] The object is further attained through a method for producing a multi-segment filter of the tobacco processing industry, whereby a group of filter segments is assembled and whereby the group of filter segments is wrapped with a first wrapping material to form a multi-segment filter, whereby the first wrapping material is compressible and/or elastic. Multi-segment filters can thus be produced that on the one hand render possible an equalization according to the invention of differences in diameter of the filter segments and in the case of decompressible material on the other hand feature an outside diameter that is uniform. It is also advantageous with the method according to the invention that conventional multi-segment filter production devices can be used, such as, e.g., the Mulfi-E of the applicant. Only the wrapping material customarily used, comprising a paper strip, needs to be replaced by a wrapping material that is compressible and/or elastic. Care should be taken here to ensure that the compressible wrapping material is not compressed on the way to the multi-segment filter. The first wrapping material is preferably essentially impermeable to smoke or completely impermeable to smoke.

[0017] If in a further process step the first wrapping material is wrapped with a second wrapping material, the subsequent handling of the multi-segment filters is simplified.

[0018] The object is further attained by the use of a compressible and/or elastic wrapping material for wrapping a group of filter segments of the tobacco processing industry for forming a multi-segment filter. Furthermore, a first wrapping material that is impermeable to smoke or essentially impermeable to smoke is preferably used for wrapping a group of filter segments of the tobacco processing industry to form a multi-segment filter.

[0019] The invention is described below without restriction of the general inventive concept on the basis of exemplary embodiments with reference to the drawings, whereby reference is expressly made to the drawings for all details of the invention not explained in further detail in the text. They show:

[0020]FIG. 1A diagrammatic side view of a multi-segment filter production device, comprising a rod forming device and a group forming device according to DE-OS 24 52 749,

[0021]FIG. 2A diagrammatic cross section view of a multi-segment filter, and

[0022]FIG. 3 An enlarged representation of a section from FIG. 2.

[0023] In the following description of the figures, in part the same elements are labeled with the same reference numbers, so that a repeated introduction has been omitted.

[0024] The multi-segment filter production device according to the prior art shown in FIG. 1 is constructed as follows:

[0025] A group forming device 2 working in transverse operation is assigned to the rod making machine 1, which group forming device features two storage containers 3 and 4 in which filter rods 6 and 7 of a first or second type are located. Removal drums 8 or 9 are located at the lower, outlet-side ends of the storage containers 3 and 4, to which removal drums respectively a cutting device 11 or 12 is assigned which severs the filter rods 6 or 7 removed from the storage containers 3 and 4. These are followed respectively by a staggering drum 13 or 14 on which the filter sections formed from the severed filter rods 6 or 7 are brought into a staggered formation and subsequently pushed through a sliding drum 16 or 17 respectively such that they form a row one after the other in a transverse axial manner. The rows of filter sections thus formed are subsequently spread apart through respectively an accelerator drum 18 or 19 so that greater spaces result between the individual filter sections.

[0026] Subsequently, the filter sections are again severed on cutting drums 21 or 22 to which likewise a cutting device 23 or 24 is respectively assigned. The again severed filter sections are at the same time spread apart again on the cutting drums 21 or 22 so that larger gaps occur between the individual elements. Subsequently elements of filter rods of the respectively other type are respectively inserted into these gaps on an assembly drum 26 and in this manner filter rod groups 27 are formed that are composed of several elements of the different filter types. The filter rod groups 27 are subsequently aligned in a longitudinally axial manner to the conveyor direction through an output means in the form of a transfer device or turning drum 28 and continuously transferred to the rod forming device 1 in a formation without gaps on a wrapping strip 31 pulled off from a bobbin 29. The transfer takes place, e.g., in accordance with DE-OS 25 34 666.

[0027] Before the filter rod groups 27 are placed on the wrapping strip 31, the latter is glued. To this end a first gluing device 32, indicated by a glue supply container 33 and two application nozzles 34 and 36, is provided which applies an interior gluing in the form of two adjacent parallel glue strips on the wrapping strip 31. A second gluing device 37, indicated by a glue storage container 38 and a glue application nozzle 39, provides the wrapping strip 31 in the area of one edge with a strip of glue for the seam gluing. Naturally, for the interior gluing also only one glue strip or also more than two glue strips can be provided if necessary.

[0028] With an application according to which the glue supply container 33 of the first gluing device 32 contains a cold glue and the supply container 38 of the second gluing device 37 contains a hot melt glue, a means 42 for bonding the interior gluing in the form of a heating device 43 is provided in the deposit area 41 of the turning drum 28 beneath the wrapping strip 31, which ensures that the interior gluing applied by the glue application nozzles 34 and 36 bonds immediately after the deposit of the filter rod groups 27, and in this manner the filter rod groups 27 are fixed on the wrapping strip 31 immediately after being deposited, so that they can no longer be displaced by outside influences, such as, e.g., by subsequent filter rod groups.

[0029] At the same time the heating device 43 activates the hot melt glue for the seam gluing. The filter rod groups 27 fixed in this manner into a row without gaps subsequently pass through a mold part in the form of a garniture chamber 44 in which the wrapping strip 31 is placed around the filter rod groups 27, so that a continuous filter rod is formed, whereby the hot melt glue for the seam gluing applied by the glue application nozzle 39 is bonded within a glue chamber 46 that is embodied to this end as a cooling device 47. The filter rod closed and sealed in this manner subsequently reaches a cutting device 48 in which combination filter rods 49 of preferably multiple unit lengths are cut off which contain respectively filter elements of the different types of filter rods 6 and 7.

[0030] Within the scope of the invention a compressible and/or elastic material is used as a wrapping strip. If a material that is only elastic is used that is provided to be wrapped around the filter segments with a corresponding pressure or under a corresponding tension or to wrap them with a corresponding tension, corresponding differences in the diameters of the filter segments can be compensated for so that the cavities occurring there are filled. However, with a material that is only elastic, this leads to the multi-segment filter ultimately formed also being embodied differently in terms of outside diameter. When a compressible wrapping material is used, there is the further advantage that the outer diameter of the multi-segment filter being formed can be correspondingly uniform. If the wrapping material is not compressible, but only elastic, there is the advantage that the processing method can be designed in a relatively uncomplicated way, since no great efforts need to be taken to ensure the wrapping material is not unintentionally compressed before the wrapping. With an exclusively compressible material, care needs to be taken to ensure the most careful possible handling of the wrapping material.

[0031] The device for producing the multi-segment filters, which has been described above, can be supplemented by a further unit that is arranged between the gluing chamber 46 or the cooling device 47 and the cutting device 48 and wraps the already closed and sealed filter rod by means of the one further wrapping strip.

[0032]FIG. 2 shows a diagrammatic cross section through a produced multi-segment filter 70 that is composed of three different filter segments 60-62 and features a first wrapping material 65 and a second wrapping material 66. In this exemplary embodiment the first wrapping material 65 is a compressible wrapping material and the second wrapping material 66 is paper. In FIG. 2, A represents the part that is shown as enlarged section in FIG. 3. In this enlarged section the diameter differences of the filter segment 61 and the filter segment 60 are shown more precisely and the equalization of these diameter differences by the compressible wrapping material 65. In this exemplary embodiment the first wrapping material 65 is an air layed fibrous web that was produced according to a method according to EP 0 032 044 B1.

[0033] A closed pore foam, such as, e.g., foam from a conventional hot melt, can also be used as the wrapping material 65. However, other compressible and/or elastic materials can also be used that are preferably impermeable to smoke or essentially impermeable to smoke. If in the simplest embodiment of the invention the first wrapping material is not impermeable to smoke, it is still very difficult for smoke to permeate it and it is much more difficult for smoke to pass through it compared with the actual filter material of the filter segments.

List of Reference Numbers

[0034]1 Rod making device 38 Supply container

[0035]2 Group forming device 41 Deposit area

[0036]3 Storage container 42 Bonding means

[0037]4 Storage container 43 Heating device

[0038]6 Filter rod 44 Garniture chamber

[0039]7 Filter rod 46 Glue chamber

[0040]8 Removal drum 47 Cooling device

[0041]9 Removal drum 48 Cutting device

[0042]11 Cutting device 49 Combination filter rods

[0043]12 Cutting device 50 Rod cutter

[0044]13 Staggering drum 60 Filter segment

[0045]14 Staggering drum -62 Filter segment

[0046]16 Sliding drum 65 Compressible wrapping material

[0047]17 Sliding drum 66 Paper

[0048]18 Accelerator drum 70 Multi-segment filter

[0049]19 Accelerator drum

[0050]21 Cutting drum

[0051]22 Cutting drum

[0052]23 Cutting device

[0053]24 Cutting device

[0054]26 Assembly drum

[0055]27 Filter rod groups

[0056]28 Turning drum

[0057]29 Bobbin

[0058]30 Bobbin mounting

[0059]31 Wrapping strip

[0060]32 Gluing device

[0061]33 Glue supply container

[0062]34 Application nozzle

[0063]36 Application nozzle

[0064]37 Gluing device 

1. Multi-segment filter (70) of the tobacco processing industry with at least two filter segments (60-62) arranged one behind the other in a longitudinally axial manner, characterized in that a compressible and/or elastic first wrapping material (65) is arranged outside around the filter segments (60-62).
 2. Multi-segment filter according to claim 1, characterized in that the first wrapping material (65) is essentially impermeable to smoke or completely impermeable to smoke.
 3. Multi-segment filter according to claim 1, characterized in that ventilation holes are provided in the first wrapping material (65).
 4. Multi-segment filter according to claim 1, characterized in that the first wrapping material (65) is the outermost layer of the multi-segment filter (70).
 5. Multi-segment filter according to claim 1, characterized in that a second wrapping material (66) is arranged outside around the first wrapping material (65).
 6. Multi-segment filter according to claim 1, characterized in that the first wrapping material (65) comprises a closed-pore foam.
 7. Multi-segment filter according to claim 6, characterized in that the closed-pore foam comprises a foamed ethylene vinyl acetate copolymer.
 8. Method for producing a multi-segment filter (70) of the tobacco processing industry, whereby a group of filter segments (60-62) is assembled and whereby the group of filter segments (60-62) is wrapped with a first wrapping material (65) to form a multi-segment filter (70), characterized in that the first wrapping material (65) is compressible and/or elastic.
 9. Method according to claim 8, characterized in that the first wrapping material (65) is impermeable to smoke or essentially impermeable to smoke.
 10. Method according to claim 8 and/or 9, characterized in that moreover in a further process step the first wrapping material (65) is wrapped with a second wrapping material (66).
 11. Use of a compressible and/or elastic first wrapping material (65) for wrapping a group of filter segments (60-62) of the tobacco processing industry to form a multi-segment filter (70).
 12. Use of a compressible and/or elastic first wrapping material (65) that is impermeable to smoke or essentially impermeable to smoke for wrapping a group of filter segments (60-62) of the tobacco processing industry to form a multi-segment filter (70). 